The invention relates to a lubrication device for lubricating traveling lubrication sites, such as those on a belt (such as a roller or chain belt), which comprises a lubricating apparatus supported so as to be displaceable back and forth in the longitudinal direction of the lubrication site motion. The lubricating apparatus includes a catch assuming a resting position and a catching position relative to the belt a similar component having the lubrication sites. The belt drives the catch in the catching position and thus drives the catch along the lubricating apparatus over a predetermined run path at the speed of the belt. A lubricating head can be moved through a lateral relative motion between the belt and the lubricating apparatus to a lubrication site, and lubricant can be supplied to At the end of the run path, the lubricating head and the catch relative to the belt return into the particular resting position, and the lubricating apparatus can be moved back along the belt into its starting position.
With such known lubrication devices, difficulties occur with lubrication site speeds above a predetermined limit value, for example of 0.4 m/sec, because the large acceleration forces occurring therein lead to the failure of the catch.
It is an object of the present invention to propose a lubrication device of the above-described type, which can be employed even with relatively high lubrication site speeds.
This object is achieved according to the invention with a lubrication device of the above described type, in which, before or simultaneously with the engagement of the catch and the belt, the lubricating apparatus can be extended in the longitudinal direction of the lubrication site motion at a boosting speed which is greater than zero and less than the speed of the belt.
In this way, it is possible to ensure that the speed difference between the lubrication sites and the lubricating apparatus before the lubricating process is not greater than the maximum speed below which a failure of the catch must be prevented.
It has been found in practice that the boosting speed of the lubricating apparatus should be no less than a predetermined maximum difference, such as for example 0.4 m/sec, less than the speed of the belt. The difference between the speed of the belt and the boosting speed is thus no greater than the permissible value of 0.4 m/sec.
Under these conditions, the boosting speed of the lubricating apparatus is preferably no more than a predetermined maximum value, for example 0.4 m/sec. If the belt runs slower than the lubricating apparatus accelerated to the boosting speed, an end position of an acceleration device (for example an acceleration cylinder) will stop and wait until it is driven by the belt in the conventional manner. Since the lubrication site speed in this case is less than approximately 0.4 m/sec, problems cannot be encountered with the catch.
In a special implementation of the invention, the boosting motion of the lubricating apparatus is provided by an acceleration device, such as an acceleration cylinder or a setting motor, if appropriate, against the effect of a return cylinder in order to avoid the rebounding of the catch from the belt.
In a further implementation of the invention, the boosting speed of the lubricating apparatus can be set, if appropriate, by a one-way restrictor valve, in order to be able to readily adapt the lubrication device to the particular conditions.
The acceleration cylinder preferably becomes pressure-free as soon as the lubricating head starts the delivery of the lubricant. After reaching the predetermined boosting speed of, for example, 0.4 m/sec, the lubricating apparatus is driven in a conventional manner by the belt under the action of the catch, and is accelerated to, for example, 0.8 m/sec.
A further characteristic of the invention is that during the return motion of the lubricating apparatus along the belt to the starting position, the acceleration cylinder can simultaneously be movable free of pressure into the starting position. The lubrication device in this case is ready for a new lubricating operation.
The speed of the return motion of the lubricating apparatus can therein be settable, if appropriate, by a one-way restrictor valve on the return cylinder.
It has been found in practice that the counter pressure of the return cylinder during the forward motion of the lubricating apparatus is approximately 0.5 bar and the return pressure of the return cylinder during the back motion of the lubricating apparatus along the belt is approximately 6 bar.
A further independent concept of the invention is that a lubrication device of a lubricating apparatus including a lubricating head, together with the catch and preferably with its aid, is movable laterally (perpendicularly) with respect to the belt. But it is also possible that the belt is movable, preferably with the aid of the catch, which is movable jointly with the lubricating apparatus along the belt, transversely to the longitudinal direction of the lubrication site motion in the direction toward the lubricating head. With the aid of the catch, the lubrication site to be lubricated is thus brought close to the lubricating head while it is laterally immovable or, conversely, the lubricating head is brought to the lubrication site.
The catch can comprise, for example, a catch arm which engages from above or below the elements of a roller or chain belt. This can take place bypivoting.
The catch arm therein preferably has at its outer end a fork-shaped member for the purpose of engaging over a roller or chain link axle.
In the event of malfunction, it is useful if the catch arm can be swung in the direction of motion of the roller or chain link axle, over which by way of example it engages, out of its path of motion. In this way, while the roller or chain belt is continuing to run, the catch can be stopped from functioning.
Known lubrication devices of this type are adapted specifically to the particular application case. Fast and flexible adaptation of the lubrication arrangement to modified rollers or chain belts with lubrication sites at varying spacings is not possible. In addition, only one lubrication site can always be supplied with lubricant in one lubricating cycle, which is a particular disadvantage in chain belts with double bearing roller pairs.
It is therefore a further object to provide a lubrication device of the above described type which can be adapted in a simple manner to different lubrication site distributions of lubrication site numbers.
This object is solved according to the invention in a lubrication device of the above described type in which two sensors are provided spaced apart from one another in the direction of motion of the belt. The sensor signals are used for detecting two lubrication sites spaced apart from one another in the longitudinal direction of the belt. For the supply of both lubrication sites, at least two lubricating heads are provided.
The invention entails an advantage that, for example, rollers or chain belts with uniformly distributed lubrication sites, as well as rollers or chain belts with varying lubrication site numbers and/or spacing and with individual support roll pairs, as well as also with double support roller pairs, can automatically be lubricated.
It is an of advantage if the spacing of the two sensors agrees substantially with the spacing of successive lubrication sites of the belt since, in this case, the signals of both sensors occur substantially concurrently.
A further characteristic of the invention is that the spacing of the sensors can be set in order to be adapted to different belts to be lubricated. This feature also applies to the lubricating head spacing.
A further invention embodiment includes, in a lubrication device of the above described type, at least two lubricating heads which, with respect to the belt oppose one another. From their respective sides, the lubricating heads can be moved in a direction toward the lubrication sites of the belt synchronously and, if appropriate, also away from the sites so that the charging forces, resulting from the lubrication pressure onto the lubricating apparatus and the belt, can be equalized.
Lubrication which is especially optimized with respect to time is brought about if the lubricating apparatus has two pairs of lubricating heads, which can be moved under control pairwise in a direction toward the lubrication sites of the belt and away from it. Such a lubrication device is particularly suitable for the lubrication of with double support roller pairs.
If the lubricating heads are disposed jointly on a carriage, this permits the common acceleration of the lubricating heads before the lubricating heads have been set onto the lubrication site. This carriage should, in this case, also support the catch.
A further characteristic of the invention is that the lubricating heads are disposed substantially mirror-symmetrically with respect to the belt disposed between them.
In particular, for the lubrication of belts, which apart from the bearing rollers also comprise guidance rollers whose axes of rotation are disposed at an angle (preferably perpendicular), to the axes of rotation of the bearing rollers, it is advantageous if the lubrication sites of the guidance rollers are lubricated with a lubrication device according to DE 200 15 780 U.